EcoPlus® Hydrovescent Air Disc® air diffusers are great for aerating or circulating nutrients in your tanks or reservoirs. These air diffusers incorporate suction cup feet to keep your Hydrovescent Air Disc® secured without fear of it moving around or flipping. The 3 air diffusers have a built-in 3/8 in 90 degree elbow fitting that insures the air line connects freely to your fitting and prevents the air line from kinking at the base of the fitting